Biodegradable polymeric nanoparticles based drug delivery systems

Cytotoxic and mutagenic potential of juglone: a comparison of free and nano-encapsulated form

Despite its evidenced beneficial herbicidal, antibacterial, antiviral, antifungal, and antioxidant effects, the application of juglone (5-hydroxy-1,4,-naphthoquinone) is limited due to its low water solubility and allelopathic and toxic effects. In recent years, research has aimed to overcome these limitations by increasing its solubility and controlling its release through nanoparticular systems. This is the first study to have synthesised and characterised juglone-loaded polymeric nanoparticles and compared them with free juglone for cytotoxicity in mouse (L929 fibroblasts) and alfalfa cells and for mutagenic potential in Salmonella typhimurium TA98/100. Mouse and plant cells treated with free and nano-encapsulated juglone showed a decrease in cell viability in a dose and time-dependent manner, but this effect was significantly lower with the nano-encapsulated form at lower doses. In the TA98 strain with S9, nano-encapsulated juglone did not exhibit mutagenic effects, unlike the free form. Since all results show that juglone encapsulation with polymeric nanoparticles reduced the toxic and mutagenic effects, it has a promising potential to be applied in medicine, food safety, and agriculture.

Pulmonary Administration: Strengthening the Value of Therapeutic Proximity

In recent years inhaled systems have shown momentum as patient-personalized therapies emerge. A significant improvement in terms of therapeutic efficacy and/or reduction adverse systemic effects is anticipated from their use owing these systems regional accumulation. Nevertheless, whatever safety and efficacy evidence required for inhaled formulations regulatory approval, it still poses an additional hurdle to gaining market access. In contrast with the formal intravenous medicines approval, the narrower adoption of pulmonary administration might rely on discrepancies in pre-clinical and clinical data provided by the marketing authorization holder to the regulatory authorities. Evidences of a diverse and inconsistent regulatory framework led to concerns over toxicity issues and respiratory safety. However, an overall trend to support general concepts of good practices exists. Current regulatory guidelines that supports PK/PD (pharmacokinetics/pharmacodynamic) assessment seeks attention threatening those inhaled formulations set to be approved in the coming years. A more complex scenario arises from the attempt of implementing nanomedicines for pulmonary administration. Cutting-edge image techniques could play a key role in supporting diverse stages of clinical development facilitating this pharmaceutics take off and speed to patients. The ongoing challenge in adapting conventional regulatory frameworks has proven to be tremendously difficult in an environment where market entry relies on multiple collections of evidence. This paper intention is to remind us that an acceptable pre-clinical toxicological program could emerge from, but not only, an accurate and robust data imaging collection. It is our conviction that if implemented, inhaled nanomedicines might have impact in multiple severe conditions, such as lung cancer, by fulfilling the opportunity for developing tailored treatments while solving dose-related toxicity issues; the most limiting threat in conventional lung cancer clinical management.

Advantages of the combined use of cyclodextrins and nanocarriers in drug delivery: A review

Complexation with cyclodextrins (CDs) has been widely and successfully used in pharmaceutical field, mainly for enhancing solubility, stability and bioavailability of a variety of drugs. However, some important drawbacks, including rapid removal from the bloodstream after in vivo administration, or possible replacement, in biological media, of the entrapped drug moieties by other molecules with higher affinity for the CD cavity, can limit the CDs effectiveness as drug carriers. This review is focused on combined strategies simultaneously exploiting CD complexation, and loading of the complexed drug into various colloidal carriers (liposomes, niosomes, polymeric nanoparticles, lipid nanoparticles, nanoemulsions, micelles) which have been investigated as a possible means for circumventing the problems associated with both such carriers, when used separately, and join their relative benefits in a unique delivery system. Several examples of applications have been reported, to illustrate the possible advantages achievable by such a dual strategy, depending on the CD-nanocarrier combination, and mainly resulting in enhanced performance of the delivery system and improved biopharmaceutical properties and therapeutic efficacy of drugs. The major problems and/or drawbacks found in the development of such systems, as well as the (rare) case of failures in achieving the expected improvements have also been highlighted.

Programing Assembling/Releasing Multifunctional miRNA Nanomedicine to Treat Prostate Cancer

MicroRNAs (miRNAs) therapy has shown to have great promise for the treatment of androgen-independent prostate cancer (AIPC) due to the low efficiency of hormonal therapy. However, instability of RNA and inefficiency of RNA therapy limit the use of miRNAs in the treatment of AIPC. Here, we report a pH/ATP-activated nanocomplexes for increasing cytosolic delivery of miR146a which can effectively inhibit the expression of epidermal growth factor receptor (EGFR) in AIPC. The nanocomplexes show identical suppressing effect in invasion, colony formation, migration ability, and growth of DU145 cells compared with Lipofectamine 2000 (lipo). But for in vivo experiments, the nanocomplexes vigorously suppress the growth of tumor volumes comparing to lipo group after five weeks' treatment. These results demonstrate the potential of the pH/ATP-activated nanocarriers for AIPC gene therapy.

Nanoparticles Based on Hydrophobic Polysaccharide Derivatives-Formation Principles, Characterization Techniques, and Biomedical Applications

Polysaccharide (PS) nanoparticles (NP) are fascinating materials that combine huge application potential with the unique beneficial features of natural biopolymers. Different types of PS-NP can be distinguished depending on the basic preparation principles (top-down vs bottom-up vs coating of nanomaterials) and the material from which they are obtained (native PS vs chemically modified PS derivatives vs nanocomposites). This review provides a comprehensive overview of an approach towards PS-NP that has gained rapidly increasing interest within the last decade; the nanoself-assembling of hydrophobic PS derivatives. This facile process is easy to perform and offers a broad structural diversity in terms of the PS backbone and the additional functionalities that can be introduced. Fundamental principles of different NP preparation techniques along with useful characterization methods are presented in this work. A comprehensive summary of PS-NP prepared by different techniques and with various PS backbones and types/amounts of hydrophobic substituents is given. The intention is to demonstrate how different parameters determine the size, size distribution, and zeta-potential of the particles. Moreover, application trends in biomedical areas are highlighted in which tailored functional PS-NP are evaluated and constantly developed further.

A novel BSA immobilizing manner on modified titanium surface ameliorates osteoblast performance

Surface modification of medical and dental devices, to improve their biocorrosion resistance and biocompatibility, can be achieved with the multidisciplinary field of biomaterials. Nanostructured titanium dioxide (TiO₂) has been employed as surface modifier of titanium-based biomaterials because it can prevent the failure of the devices due to wear mechanisms. Moreover, this oxide surface is mostly terminated by hydroxyl groups (-OH) that can be directly functionalized with biomolecules to improve the biocompatibility of these devices. We explored the influence of 3-aminopropyltrimethoxysilane (APTMS) molecules as spacers in bovine serum albumin (BSA) protein immobilization on the physically hydroxylated surfaces of rutile phase TiO₂ films grown by reactive Radio Frequency (RF) magnetron sputtering. X-ray Photoelectron Spectroscopy (XPS) was used to examine the adsorption of BSA and APTMS on the hydroxylated surface of TiO₂ thin films. For biological tests, BSA was directly immobilized on the film surface and on the APTMS monolayer. Biological analysis found better osteoblast performance considering gene markers related to cell adhesion after interacting directly with the surface modified by the immobilization of BSA, especially on the surface where this protein was immobilized by APTMS. Additionally, we addressed the relevance of this biointerfaces on extracellular matrix remodeling by zymography analysis. Altogether, our data provides new insights about the cellular and molecular mechanisms covering the improved osteoblastic response of the proposed surface modification.

New Vision for Visual Prostheses

Developments of new strategies to restore vision and improving on current strategies by harnessing new advancements in material and electrical sciences, and biological and genetic-based technologies are of upmost health priorities around the world. Federal and private entities are spending billions of dollars on visual prosthetics technologies. This review describes the most current and state-of-the-art bioengineering technologies to restore vision. This includes a thorough description of traditional electrode-based visual prosthetics that have improved substantially since early prototypes. Recent advances in molecular and synthetic biology have transformed vision-assisted technologies; For example, optogenetic technologies that introduce light-responsive proteins offer excellent resolution but cortical applications are restricted by fiber implantation and tissue damage. Other stimulation modalities, such as magnetic fields, have been explored to achieve non-invasive neuromodulation. Miniature magnetic coils are currently being developed to activate select groups of neurons. Magnetically-responsive nanoparticles or exogenous proteins can significantly enhance the coupling between external electromagnetic devices and any neurons affiliated with these modifications. The need to minimize cytotoxic effects for nanoparticle-based therapies will likely restrict the number of usable materials. Nevertheless, advances in identifying and utilizing proteins that respond to magnetic fields may lead to non-invasive, cell-specific stimulation and may overcome many of the limitations that currently exist with other methods. Finally, sensory substitution systems also serve as viable visual prostheses by converting visual input to auditory and somatosensory stimuli. This review also discusses major challenges in the field and offers bioengineering strategies to overcome those.

Mucoadhesive-to-penetrating controllable peptosomes-in-microspheres co-loaded with anti-miR-31 oligonucleotide and Curcumin for targeted colorectal cancer therapy

Background: Accumulating evidences indicate that nanomedicines greatly decrease the side effects and enhance the efficacy of colorectal cancer (CRC) treatment. In particular, the use of rectal delivery of nanomedicines, with advantages such as fast therapeutic effects and a diminishing hepatic first-pass effect, is currently emerging. Method: We established a CRC targeted delivery system, in which α-lactalbumin peptosomes (PSs) co-loaded with a microRNA (miR)-31 inhibitor (miR-31i) and curcumin (Cur) were encapsuslated in thiolated TEMPO oxidized Konjac glucomannan (sOKGM) microspheres, referred as sOKGM-PS-miR-31i/Cur. The CRC targeting capability, drug release profiles, mucoadhesive-to-penetrating properties and therapeutic efficacy of sOKGM-PS-miR-31i/Cur delivery system were evaluated in colorectal cancer cells and azoxymethane-dextran sodium (AOM-DSS) induced tumor models. Results: sOKGM-PS-miR-31i/Cur delivery system were stable in the harsh gastrointestinal environment after rectal or oral administration; and were also mucoadhesive due to disulfide bond interactions with the colonic mucus layer, resulting in an enhanced drug retention and local bioavailability in the colon. Concomitantly, the released PS-miR-31i/Cur PSs from the microsphere was mucus-penetrating, efficiently passing through the colonic mucus layer, and allowed Cur and miR-31i specifically target to colon tumor cells with the guide of CD133 targeting peptides. Consequently, rectal delivery of sOKGM-PS-miR-31i/Cur microspheres suppressed tumor growth in an azoxymethane-dextran sodium sulfate (AOM-DSS)-induced tumor model. Conclusion: sOKGM-PS-miR-31i/Cur microspheres are effective rectal delivery system with combined advantages of mucoadhesive and mucus-penetrating properties, representing a potent and viable therapeutic approach for CRC.

Long-Acting Paliperidone Parenteral Formulations Based on Polycaprolactone Nanoparticles; the Influence of Stabilizer and Chitosan on In Vitro Release, Protein Adsorption, and Cytotoxicity

Long-acting preparations containing the antipsychotic paliperidone for intramuscular injection has drawn considerable attention to achieve harmless long-term treatment. This study aimed to develop paliperidone loaded polycaprolactone (PCL) nanoparticles and investigate the influence of PCL/drug ratio, stabilizer type, and chitosan coating on physicochemical properties, protein adsorption, and cellular toxicity. Results showed that chitosan coating produced enlarged particle sizes, shifted the surface charges from negative into positive and did not influence encapsulation efficiencies. Chitosan coating relatively sustained the drug release especially in pluronic stabilized formulations. Pluronic F127 based formulations exhibited the least protein adsorption (384.3 μg/mL). Chitosan coating of Tween 80 and polyvinyl alcohol stabilized formulations significantly (p < 0.05) increased protein adsorption. Cellular viability was concentration-dependent and negatively affected by stabilizers. All formulations did not show cellular death at 1.56 μg/mL. Inflammatory responses and oxidative stress were less affected by Tween 80 compared with other stabilizers. Chitosan minimized all aspects of cellular toxicity. Collectively, stabilizer type and chitosan coating play critical roles in developing safe and effective long-acting PCL nanoparticles intended for parenteral drug delivery. The coated formulations containing Tween 80 and Pluronic F127 as stabilizers are warranted a future in vivo study to delineate its safety and efficacy profiles.

Pros and cons in prion diseases abatement: Insights from nanomedicine and transmissibility patterns

Ample research progress with nanotechnology applications in health and medicine implies precision and accuracy in the scenario of neurodegenerative disorders, for which impending research in ultimate and complete cure has been the vision worldwide. The complexity of prion disease has been unravelled by scientists and demarcated for efficient abatement protocols, but which are still under research and clinical trials. Drug delivery strategies combating prion diseases across the blood brain barrier, the efficacy of drugs and biocompatibility remain a serious question to be thoroughly studied for effective diagnosis and treatment. The present review compiles comprehensively the current treatment modalities against prion diseases and future prospects of nanotechnology addressing diagnosis and treatment of prion diseases with a special emphasis on transmissibility. Further, approaches for anti-prion technology, immunotherapy, and hindrances in vaccine development are discussed.

Preparation and Characterization of Chitosan Grafting Hydrogel for Mine-Fire Fighting

Mine fires are one of the primary natural disasters in coal production. The majority of mine fires are caused by the spontaneous combustion of coal. To reduce the risk of spontaneous combustion of coal, a new fire prevention and extinguishing hydrogel has been developed. Poly(acrylic acid-co-methacrylamide) (P(AA-co-MAA)) and chitosan-grafted poly(acrylic acid-co-methacrylamide) (CTS-g-P(AA-co-MAA)) were prepared by aqueous solution polymerization, and their characteristics have been studied by scanning electron microscopy and Fourier transform infrared spectroscopy. The swelling ability and water retention of the hydrogels were also tested and compared. The experimental results showed that the grafting of chitosan can improve the water-absorbing ability of the hydrogel in acidic solution and deionized water and enhance the water retention of the hydrogel. The thermogravimetric experiments of the mixture of the hydrogel and coal showed that the thermal stability of the mixture was the best when the ratio of hydrogel to coal was 1:10, and the grafting of chitosan did not weaken the thermal stability of the hydrogel. In addition, the thermogravimetry and differential scanning calorimetry measurement of coal with the hydrogel in air proved that the CTS-g-P(AA-co-MAA) hydrogel effectively prevented the initial oxidation of coal. Thus, CTS-g-P(AA-co-MAA) is recommended as an inhibitor in preventing coal oxidation.

The Design of Poly(lactide-co-glycolide) Nanocarriers for Medical Applications

Polymeric biomaterials have found widespread applications in nanomedicine, and poly(lactide-co-glycolide), (PLGA) in particular has been successfully implemented in numerous drug delivery formulations due to its synthetic malleability and biocompatibility. However, the need for preconception in these formulations is increasing, and this can be achieved by selection and elimination of design variables in order for these systems to be tailored for their specific applications. The starting materials and preparation methods have been shown to influence various parameters of PLGA-based nanocarriers and their implementation in drug delivery systems, while the implementation of computational simulations as a component of formulation studies can provide valuable information on their characteristics. This review provides a critical summary of the synthesis and applications of PLGA-based systems in bio-medicine and outlines experimental and computational design considerations of these systems.

Physicochemical Evaluation of Insulin Complexes with QPDMAEMA-b-PLMA-b-POEGMA Cationic Amphiphlic Triblock Terpolymer Micelles

Herein, poly[quaternized 2-(dimethylamino)ethyl methacrylate-b-lauryl methacrylate-b-(oligo ethylene glycol)methacrylate] (QPDMAEMA-b-PLMA-b-POEGMA) cationic amphiphilic triblock terpolymers were used as vehicles for the complexation/encapsulation of insulin (INS). The terpolymers self-assemble in spherical micelles with PLMA cores and mixed QPDMAEMA/POEGMA coronas in aqueous solutions. The cationic micelles were complexed via electrostatic interactions with INS, which contains anionic charges at pH 7. The solutions were colloidally stable in all INS ratios used. Light-scattering techniques were used for investigation of the complexation ability and the size and surface charge of the terpolymer/INS complexes. The results showed that the size of the complexes increases as INS ratio increases, while at the same time the surface charge remains positive, indicating the formation of clusters of micelles/INS complexes in the solution. Fluorescence spectroscopy measurements revealed that the conformation of the protein is not affected after the complexation with the terpolymer micellar aggregates. It was observed that as the solution ionic strength increases, the size of the QPDMAEMA-b-PLMA-b-POEGMA/INS complexes initially decreases and then remains practically constant at higher ionic strength, indicating further aggregation of the complexes. atomic force microscopy (AFM) measurements showed the existence of both clusters and isolated nanoparticulate terpolymer/protein complexes.

pH-responsive polymeric nanoparticles with tunable sizes for targeted drug delivery

Biodegradable nanoparticles (NPs) have shown great promise as intracellular imaging probes, nanocarriers and drug delivery vehicles. In this study, we designed and prepared amphiphilic cellulose derivatives via Schiff base reactions between 2,3-dialdehyde cellulose (DAC) and amino compounds. Polymeric NPs were facilely fabricated via the self-assembly of the as-synthesized amphiphilic macromolecules. The size distribution of the obtained NPs can be tuned by changing the amount and length of the grafted hydrophobic side-chains. Anticancer drugs (DOX) were encapsulated in the NPs and the drug-loaded NPs based on cellulose derivatives were stable in neutral and alkaline environments for at least a month. They rapidly decomposed with the efficient release of the drug in acidic tumor microenvironments. These drug-loaded NPs have the potential for application in cancer treatment.

Development of a Biodegradable Subcutaneous Implant for Prolonged Drug Delivery Using 3D Printing

Implantable drug delivery devices offer many advantages over other routes of drug delivery. Most significantly, the delivery of lower doses of drug, thus, potentially reducing side-effects and improving patient compliance. Three dimensional (3D) printing is a flexible technique, which has been subject to increasing interest in the past few years, especially in the area of medical devices. The present work focussed on the use of 3D printing as a tool to manufacture implantable drug delivery devices to deliver a range of model compounds (methylene blue, ibuprofen sodium and ibuprofen acid) in two in vitro models. Five implant designs were produced, and the release rate varied, depending on the implant design and the drug properties. Additionally, a rate controlling membrane was produced, which further prolonged the release from the produced implants, signalling the potential use of these devices for chronic conditions.

Oral nanoparticles based on gellan gum/pectin for colon-targeted delivery of resveratrol

Nanoparticles based on gellan gum/pectin blends were designed for colon-targeted release of resveratrol (RES). Their impact on drug release rates and permeability were evaluated using Caco-2 cell model and mucus secreting triple co-culture model. Polymeric nanoparticles (PNP) were successfully prepared by nebulization/ionotropic gelation, achieving high drug loading (>80%). PNP were spherical with a low positive charge density (+5mV) and exhibited diameters of around 330 nm. Developed PNP were able to promote effective modulation of drug release rates, so that only 3% of RES was released in acidic media over 2 h, and, in pH 6.8, the drug was released in a sustained manner, reaching 85% in 30 h. The permeability of RES-loaded PNP in the Caco-2 model was 0.15%, while in the triple co-culture model, in the presence of mucus, it reached 5.5%. The everted gut sac experiment corroborated the low permeability of RES-loaded PNP in the presence or absence of mucus and highlighted their high ability to interact with the intestinal tissue. Results indicate that the novel PNP developed in this work are safe and promising carriers for controlled delivery of RES at the colon.

Stimuli Responsive In Situ Gelling Systems Loaded with PLGA Nanoparticles of Moxifloxacin Hydrochloride for Effective Treatment of Periodontitis

The objectives of the present research work were systematic development of novel in situ gel formulation containing nanoparticles for localised delivery of moxifloxacin against bacterial periodontitis. PLGA nanoparticles were prepared and optimised in a systematic manner. Factor screening was performed with the help of half-factorial design to identify the influential factors, while response surface optimisation of the nanoparticles was conducted using central composite design. The optimum nanoparticle formulation was chosen on the basis of lower particle size, higher drug entrapment and controlled drug release characteristics up to 1 week time period, while the optimum in situ gel was selected on the basis of faster gelling and higher viscosity and gel strength properties for improved retention in the periodontium. In vivo histopathological studies and in vivo gamma scintigraphy studies revealed the extended release, superior efficacy and enhanced retention of nanoparticle-loaded in situ gelling system. Results obtained from in vivo histopathological studies after 1 week treatment with in situ gel formulation containing nanoparticles of moxifloxacin were found to be better than with 3 weeks treatment of marketed gel formulation. Overall, the studies ratify successful development of an effective site-specific drug delivery system with enhanced biopharmaceutical attributes for the periodontitis treatment.

Mesoporous Silica Nanoparticles for the Treatment of Complex Bone Diseases: Bone Cancer, Bone Infection and Osteoporosis

Bone diseases, such as bone cancer, bone infection and osteoporosis, constitute a major issue for modern societies as a consequence of their progressive ageing. Even though these pathologies can be currently treated in the clinic, some of those treatments present drawbacks that may lead to severe complications. For instance, chemotherapy lacks great tumor tissue selectivity, affecting healthy and diseased tissues. In addition, the inappropriate use of antimicrobials is leading to the appearance of drug-resistant bacteria and persistent biofilms, rendering current antibiotics useless. Furthermore, current antiosteoporotic treatments present many side effects as a consequence of their poor bioavailability and the need to use higher doses. In view of the existing evidence, the encapsulation and selective delivery to the diseased tissues of the different therapeutic compounds seem highly convenient. In this sense, silica-based mesoporous nanoparticles offer great loading capacity within their pores, the possibility of modifying the surface to target the particles to the malignant areas and great biocompatibility. This manuscript is intended to be a comprehensive review of the available literature on complex bone diseases treated with silica-based mesoporous nanoparticles-the further development of which and eventual translation into the clinic could bring significant benefits for our future society.

Synthesis and quantitative analyses of acrylamide-grafted poly(lactide-co-glycidyl methacrylate) amphiphilic copolymers for environmental and biomedical applications

Bio-degradable/bio-compatible poly(lactide-co-glycidyl methacrylate), P(LA-co-GMA), a copolymer has been synthesized. The material contains curable CC groups, which enable its self-curing and grafting reactions with other vinyl monomers. The copolymer was grafted with a pH-responsive polyacrylamide (PAAm), by UV-assisted reactions using acrylamide (AAm) and N,N'-methylene bisacrylamide monomers, and various photoinitiator systems. The original copolymer and its partially-cured counterpart were employed in the grafting reaction. Chemical structures and properties of the resulting materials were characterized. Standard quantitative analysis techniques for measurement of the grafted AAm content and the degree of CC conversion have been developed by ¹H NMR and FTIR spectroscopy. FTIR offers more advantages, in terms of non-destructive analysis, ease of operation, and lower cost of analysis. The results show that the grafted products from pre-cured P(LA-co-GMA) copolymers contain higher grafted AAm contents than their uncured counterparts. The highest grafted AAm content was obtained by using benzophenone (BP) as an initiator, while camphorquinone (CQ) led to the lowest content. In contrast, the degree of CC conversion of the copolymer from the two initiator systems shows a reverse trend. These amphiphilic and pH-responsive grafted copolymers with tunable AAm contents have a high potential for use in various applications, especially in biomedical and environmental fields.

Anticancer efficacy of 6-thioguanine loaded chitosan nanoparticles with or without curcumin

6-Thioguanine encapsulated chitosan nanoparticles (6-TG-CNPs) has formulated by the ionic-gelation method. Morphologically, the 6-TG-CNPs were spherical and showed mean size, PDI, zeta potential, and entrapment efficiency of 261.63 ± 6.01 nm, 0.34 ± 0.10, +15.97 ± 0.46 mV and 44.27%, respectively. The IR spectra confirmed the 6-TG complex with chitosan. The in vitro drug release profile of 6-TG-CNPs revealed an increase in sustained-release (91.40 ± 1.08% at 48 h) at pH 4.8 compared to less sustained-release (73.96 ± 1.12% at 48 h) at pH 7.4. The MTT assay was conducted on MCF-7 and PA-1 cell lines at 48 h incubation to determine % cell viability. The IC₅₀ values of 6-TG, 6-TG-CNPs, and curcumin for MCF-7 were 23.09, 17.82, and 15.73 μM, respectively. Likewise, IC₅₀ values of 6-TG, 6-TG-CNPs, and curcumin for PA-1 were 5.81, 3.92, and 12.89 μM, respectively. A combination of 6-TG-CNPs (IC₂₅) with curcumin (IC₂₅) on PA-1 and MCF-7 showed % cell viability of 43.67 ± 0.02 and 49.77 ± 0.05, respectively. The in vitro cytotoxicity potential in terms of % cell viability, early apoptosis, G2/M phase arrest, and DNA demethylating activity of 6-TG-CNPs alone and combination with curcumin proved to be more effective than that of 6-TG on PA-1 cells.

Disassembly of Nanospheres with a PEG Shell upon Adsorption onto PEGylated Substrates

Polymeric nanospheres have the ability to encapsulate drugs and are therefore widely used in drug delivery applications. Structural transformations that affect drug release from nanospheres are governed by the surrounding environment. To understand these effects, we investigated the adsorption behavior of three types of nanospheres onto model surfaces using quartz crystal microbalance with dissipation (QCM-D) and by atomic force microscopy (AFM). Substrates were prepared from polymers with different degrees of PEGylation (0, 1, and 15%). Nanospheres were prepared via self-assembly of block copolymers. Tyrosine-derived nanospheres are A-B-A triblock copolymers with methoxy poly(ethylene glycol) (PEG) as the A-blocks and an alternating copolymer of desaminotyrosyl-tyrosine octyl ester and suberic acid oligo(DTO-SA) as the B-block. On non-PEGylated substrates, these nanospheres assembled into a close-packed structure; on PEGylated substrates, the adsorbed nanospheres formed a continuous film, thinner than the size of the nanospheres suggesting unraveling of the PEG corona and disassembly of the nanospheres. Also, the adsorption was concentration-dependent, the final thickness being attained at exponentially longer times at lower concentrations. Such substrate- and concentration-dependent behavior was not observed with Pluronic F-127 and PEG-poly(caprolactone) (PCL) nanospheres. Since the essential difference among the three nanospheres is the composition of the core, we conclude that the core influences the adsorption characteristics of the nanospheres as a consequence of their disassembly upon adsorption. These results are expected to be useful in designing nanospheres for their efficient transport across vascular barriers and for delivering drugs to their targets.

Multifunctional Polymeric Nanoplatforms for Brain Diseases Diagnosis, Therapy and Theranostics

The blood-brain barrier (BBB) acts as a barrier to prevent the central nervous system (CNS) from damage by substances that originate from the blood circulation. The BBB limits drug penetration into the brain and is one of the major clinical obstacles to the treatment of CNS diseases. Nanotechnology-based delivery systems have been tested for overcoming this barrier and releasing related drugs into the brain matrix. In this review, nanoparticles (NPs) from simple to developed delivery systems are discussed for the delivery of a drug to the brain. This review particularly focuses on polymeric nanomaterials that have been used for CNS treatment. Polymeric NPs such as polylactide (PLA), poly (D, L-lactide-co-glycolide) (PLGA), poly (ε-caprolactone) (PCL), poly (alkyl cyanoacrylate) (PACA), human serum albumin (HSA), gelatin, and chitosan are discussed in detail.

Drug Delivery with Polymeric Nanocarriers-Cellular Uptake Mechanisms

Nanocarrier-based systems hold a promise to become "Dr. Ehrlich's Magic Bullet" capable of delivering drugs, proteins and genetic materials intact to a specific location in an organism down to subcellular level. The key question, however, how a nanocarrier is internalized by cells and how its intracellular trafficking and the fate in the cell can be controlled remains yet to be answered. In this review we survey drug delivery systems based on various polymeric nanocarriers, their uptake mechanisms, as well as the experimental techniques and common pathway inhibitors applied for internalization studies. While energy-dependent endocytosis is observed as the main uptake pathway, the integrity of a drug-loaded nanocarrier upon its internalization appears to be a seldomly addressed problem that can drastically affect the uptake kinetics and toxicity of the system in vitro and in vivo.

Novel chitosan-based pH-responsive lipid-polymer hybrid nanovesicles (OLA-LPHVs) for delivery of vancomycin against methicillin-resistant Staphylococcus aureus infections

The development of novel materials is necessary for adequate delivery of drugs to combat the Methicillin-resistant Staphylococcus aureus (MRSA) burden due to the limitations of conventional methods and challenges associated with antimicrobial resistance. Hence, this study aimed to synthesise a novel oleylamine based zwitterionic lipid (OLA) and explore its potential to formulate chitosan-based pH-responsive lipid-polymer hybrid nanovesicles (VM-OLA-LPHVs1) to deliver VM against MRSA. The OLA was synthesised, and the structure characterised by ¹H NMR, ¹³C NMR, FT-IR and HR-MS. The preliminary biocompatibility of OLA and VM-OLA-LPHVs1 was evaluated on HEK-293, A-549, MCF-7 and HepG-2 cell lines using in vitro cytotoxicity assay. The VM-OLA-LPHVs1 were formulated by ionic gelation method and characterised in order to determine the hydrodynamic diameter (D_H), morphology in vitro and in vivo antibacterial efficacy. The result of the in vitro cytotoxicity study revealed cell viability of above 75% in all cell lines when exposed to OLA and VM-OLA-LPHVs1, thus indicating their biosafety. The VM-OLA-LPHVs1 had a D_H, polydispersity index (PDI), and EE% of 198.0 ± 14.04 nm, 0.137 ± 0.02, and 45.61 ± 0.54% respectively at physiological pH, with surface-charge (ζ) switching from negative at pH 7.4 to positive at pH 6.0. The VM release from the VM-OLA-LPHVs1 was faster at pH 6.0 compared to physiological pH, with 97% release after 72-h. The VM-OLA-LPHVs1 had a lower minimum inhibitory concentration (MIC) value of 0.59 μg/mL at pH 6.0 compared to 2.39 μg/mL at pH 7.4, against MRSA with 52.9-fold antibacterial enhancement. The flow cytometry study revealed that VM-OLA-LPHVs1 had similar bactericidal efficacy on MRSA compared to bare VM, despite an 8-fold lower VM concentration in the nanovesicles. Additionally, fluorescence microscopy study showed the ability of the VM-OLA-LPHVs1 to eliminate biofilms. The electrical conductivity, and protein/DNA concentration, increased and decreased respectively, as compared to bare VM which indicated greater MRSA membrane damage. The in vivo studies in a BALB/c mouse-infected skin model treated with VM-OLA-LPHVs1 revealed 95-fold lower MRSA burden compared to the group treated with bare VM. These findings suggest that OLA can be used as an effective novel material for complexation with biodegradable polymer chitosan (CHs) to form pH-responsive VM-OLA-LPHVs1 nanovesicles which show greater potential for enhancement and improvement of treatment of bacterial infections.

Monodisperse Al-Doped ZnO/Perovskite Nanocapsule

We developed monodisperse ZnO nanocapsules and atmospheric N plasma was used to develop a ZnO-organic nanocomposite. To test the seal of the ZnO nanocapsule, the halide perovskite CH₃NH₃PbBr₃ was used as the filler. Al atoms were doped into ZnO nanorods to increase the conductivity of ZnO nanorods. A green emission peak located at 535 nm was observed in the nanocapsules with a 410 nm excitation because of the free-exciton recombination of CH₃NH₃PbBr₃. The Al-doped ZnO (AZO)/CH₃NH₃PbBr₃ nanocapsules was further tested under using a three-electrode photoelectrochemistry cell. AZO/CH₃NH₃PbBr₃ nanocapsule arrays yield an elevated photocurrent of approximately 0.2 mA/cm² at 1 V versus Ag/AgCl under air mass 1.5 (AM 1.5), almost 1.5 times larger than that of the AZO nanorod arrays. The photo-current stability of AZO/CH₃NH₃PbBr₃ nanocapsule arrays photoelectrode is better than that of AZO nanorod arrays under a repeated on/off light test. This confirmed that the AZO/CH₃NH₃PbBr₃ nanocapsules had been successfully sealed and that the degradation of CH₃NH₃PbNBr₃ was thus dramatically reduced. Our study yields a novel platform for nanoscale optical and optoelectronic devices or for delivery of highly toxic drugs.

Hydrogels as Potential Nano-, Micro- and Macro-Scale Systems for Controlled Drug Delivery

This review is an extensive evaluation and essential analysis of the design and formation of hydrogels (HGs) for drug delivery. We review the fundamental principles of HGs (their chemical structures, physicochemical properties, synthesis routes, different types, etc.) that influence their biological properties and medical and pharmaceutical applications. Strategies for fabricating HGs with different diameters (macro, micro, and nano) are also presented. The size of biocompatible HG materials determines their potential uses in medicine as drug carriers. Additionally, novel drug delivery methods for enhancing treatment are discussed. A critical review is performed based on the latest literature reports.

Protein-loaded soluble and nanoparticulate formulations of ionic polyphosphazenes and their interactions on molecular and cellular levels

Nanoparticulate and water-soluble formulations of ionic polyphosphazenes and protein cargo - lysozyme (LYZ) were prepared by their self-assembly in aqueous solutions at near physiological pH (pH 7.4) in the presence and absence of an ionic cross-linker - spermine tetrahydrochloride. Efficiency of LYZ encapsulation, physico-chemical characteristics of formulations, and the effect of reaction parameters were investigated using asymmetric flow field flow fractionation (AF4) and dynamic light scattering (DLS) methods. The effect of both polymer formulations on encapsulated LYZ was evaluated using soluble oligosaccharide substrate, whereas their ability to present the protein to cellular surfaces was assessed by measuring enzymatic activity of encapsulated LYZ against Micrococcus lysodeikticus cells. It was found that both soluble and cross-linked polymer matrices reduce lysis of bacterial cells by LYZ, whereas activity of encapsulated protein against oligosaccharide substrate remained practically unchanged indicating no adverse effect of polyphosphazene on protein integrity. Moreover, nanoparticulate formulations display distinctly different behavior in cellular assays when compared to their soluble counterparts. LYZ encapsulated in polyphosphazene nanoparticles shows approximately 2.5-fold higher activity in its ability to lyse cells as compared with water-soluble LYZ-PCPP formulations. A new approach to PEGylation of polyphosphazene nanoparticles was also developed. The method utilizes a new ionic polyphosphazene derivative, which contains graft (polyethylene glycol) chains. PEGylation allows for an improved control over the size of nanoparticles and broader modulation of their cross-linking density, while still permitting for protein presentation to cellular substrates.

Functional DNA-based hydrogel intelligent materials for biomedical applications

Multifunctional intelligent DNA hydrogels have been reviewed for many biomedical applications.

Self-assembly of paramagnetic amphiphilic copolymers for synergistic therapy

Theranostic nanoparticles composed of amphiphilic paramagnetic polymers are assembled for dual mode imaging and synergistic therapy.

Biodegradable reduction and pH dual-sensitive polymer micelles based on poly(2-ethyl-2-oxazoline) for efficient delivery of curcumin

A series of disulfide-linked amphiphilic polymers polyoxaline-SS-poly(lactide) (PEtOx-SS-PLA) were prepared and self-assembled into nano-micelles in water.

Amphiphilic poly(caprolactone-b-N-hydroxyethyl acrylamide) micelles for controlled drug delivery

To increase the bioavailability and water solubility of hydrophobic medicine, an amphiphilic block copolymer, polycaprolactone-block-polyhydroxyethyl acrylamide (PCL-b-PHEAA), was synthesized.

Facile preparation of long-chain aliphatic polycarbonates containing block copolycarbonates via one-pot sequential organic catalyzed polymerization of macrocyclic carbonates and trimethylene carbonates

A universal and effective approach was reported to synthesize block copolycarbonates containing long-chain aliphatic polycarbonates and PTMC segments using the ROP differences between macrocyclic and small cyclic carbonates with TBD as catalyst.

Supramolecular behaviour and fluorescence of rhodamine-functionalised ROMP polymers

A ROMP platform leading to rhodamine B containing amphiphilic block copolymers, which self-assemble into micelles which are able to sequester molecular dyes and interact with them by energy transfer. The polymer micelles do not interact with DNA.

Preparation of a size selective nanocomposite through temperature assisted co-assembly of gelatin and pluronic F127 for passive targeting of doxorubicin

The study demonstrates the importance of the weight ratio of F127 and gelatin in forming size selective nanoconjugate through a thermal relaxation approach and its potential as an efficient drug delivery system of doxorubicin with reduced side effects.

Oral and Intra-nasal Administration of Nanoparticles in the Cerebral Ischemia Treatment in Animal Experiments: Considering its Advantages and Disadvantages

BACKGROUND

Over the past few decades, nanotechnology has dramatically advanced; from the precise strategies of synthesizing modern nanostructures to methods of entry into the body. Using nanotechnology in diagnosis, drug delivery, determining signaling pathways, and tissue engineering is great hope for the treatment of stroke. The drug-carrying nanoparticles are a way to increase drug absorption through the mouth or nose in treating the stroke.

OBJECTIVE

In this article, in addition to explaining pros and cons of oral and intra-nasal administration of nanoparticles in the brain ischemia treatment of animal models, the researchers introduce some articles in this field and briefly mentioned their work outcomes.

METHODS

A number of relevant published articles 183 were initially collected from three popular databases including PubMed, Google Scholar, and Scopus. The articles not closely related to the main purpose of the present work were removed from the study process. The present data set finally included 125 published articles.

RESULTS

Direct delivery of the drug to the animal brain through the mouth and nose has more therapeutic effects than systemic delivery of drugs. The strategy of adding drugs to the nanoparticles complex can potentially improve the direct delivery of drugs to the CNS.

CONCLUSION

Despite the limitations of oral and intra-nasal routes, the therapeutic potential of oral and intra-nasal administration of nano-medicines is high in cerebral ischemia treatment.

Photodynamic cancer therapy enhances accumulation of nanoparticles in tumor-associated myeloid cells

In cancer treatment, nanomedicines may be employed in an attempt to improve the tumor localization of antineoplastic drugs e.g. immunotherapeutic agents either through passive or active targeting, thereby potentially enhancing therapeutic effect and reducing undesired off-target effects. However, a large number of administrated nanocarriers often fail to reach the tumor area. In the present study, we show that photodynamic therapy (PDT) enhances the tumor accumulation of systemically administered lipid-PEG layer coated poly (lactic-co-glycolic acid) (PLGA) nanoparticles (NP). Intravital microscopy and histological analysis of the tumor area reveal that the tumor vasculature was disrupted after PDT, disturbing blood flow and coinciding with entrapment of nanocarriers in the tumor area. We observed that the nanoparticles accumulating after treatment do not confine to specific locations within the tumor, but rather localize to various cells present throughout the tumor area. Finally, we show by flow cytometry that NP accumulation occurred mostly in immune cells of the myeloid lineage present in the tumor microenvironment (TME) as well as in tumor cells, albeit to a lower extent. These data expose opportunities for combination treatments of clinical PDT with NP-based immunotherapy to modulate the TME and improve antitumor immune responses.

Neutrophil membranes coated, antibiotic agent loaded nanoparticles targeting to the lung inflammation

Natural cellular membranes, with the outstanding qualities of biocompatibility and specificity, have gained growing attentions in the system of drug delivery. Nanoparticles coated with cellular membranes are starting to be applied as drug-loaded-vehicles to target tumors. Here, neutrophil membranes were selected to apply in the treatment of inflammation because neutrophils can participate in various inflammatory responses and accumulate at inflammatory sites to eliminate pathogens. Through extracting neutrophil membranes from natural neutrophils without affecting their biological properties, nanoparticles loaded with sparfloxacin (SPX) were coated with these membranes and disguised as neutrophils. Compared with traditional nano-medicines, the neutrophil membrane-coated nanoparticles (NM-NP-SPX) possessed precise targeting ability just like the neutrophils could accumulate at inflammatory sites when inflammation burst. In addition, NM-NP-SPX could prolong the circulation time and had the property of controlled-release. Through in vivo experiments, we found that the concentration of three representative inflammatory cytokines in blood, bacteria and inflammatory cells in lungs of the mice with pneumonia reduced significantly in the initial 24 h after the injection of NM-NP-SPX, which meant that NM-NP-SPX could greatly reduce the risk of death for the patients with inflammation. Moreover, the infected lungs could recover rapidly without any side effects to other organs due to the low cytotoxicity of NM-NP-SPX against normal cells. Therefore, our developed drug delivery system has enormous advantages in treating inflammations. Not only that, this kind of bionic method may have greater value and application prospects in curing the inflammations arisen from cancers.

Development of Methotrexate and Minocycline Loaded Nanoparticles for the Effective Treatment of Rheumatoid Arthritis

Rheumatoid arthritis is an autoimmune disease that leads to cartilage destruction, synovial joint inflammation, and bacterial joint/bone infections. In the present work, methotrexate and minocycline-loaded nanoparticles (MMNPs) were developed with an aim to provide relief from inflammation and disease progression/joints stiffness and to control the bacterial infections associated with rheumatoid arthritis. MMNPs were developed and optimized by solvent evaporation along with high-pressure homogenization technique using poly(lactic-co-glycolic acid) (50:50%) copolymer. FTIR spectrometric results showed the compatibility nature of methotrexate, minocycline, and poly(lactic-co-glycolic acid). The MMNPs showed particle size ranging from 125.03 ± 9.82 to 251.5 ± 6.23 nm with charge of around - 6.90 ± 0.8 to - 34.8 ± 4.3 mV. The in vitro release studies showed a sustained release pattern with 75.11% of methotrexate (MTX) release and 49.11% of minocycline hydrochloride (MNC) release at 10 h. The developed MMNPs were found to be stable at refrigerated condition and non-hemolytic nature (< 22.0%). MMNPs showed superior cytotoxicity for studied concentrations (0.1 to 1000 μM) compared with free MTX at both 24 and 48 h treatment period in a dose/time-dependent manner in inflammatory RAW 264.7 cells. Anti-bacterial studies indicate that the efficacy of the developed MMNPs to control infections was compared with pure MNC. In vivo anti-arthritis showed effective arthritis reduction potential of the developed MMNPs upon intravenous administration. This proof of concept implies that MTX with MNC combined nanoparticles may be effective to treat RA associated with severe infections. Graphical abstract.

Advanced Approaches of Bioactive Peptide Molecules and Protein Drug Delivery Systems

Despite the fact that protein and peptide therapeutics are widely employed in the treatment of various diseases, their delivery is posing an unembellished challenge to the scientists. It was discovered that delivery of these therapeutic systems through oral route is easy with high patient compliance. However, proteolytic degradation and absorption through the mucosal epithelium are the barriers in this route. These issues can be minimized by the use of enzyme inhibitors, absorption enhancers, different carrier systems or either by direct modification. In the process of investigation, it was found that transdermal route is not posing any challenges of enzymatic degradation, but, still absorption is the limitation as the outer layer of skin acts as a barrier. To suppress the effect of the barrier and increase the rate of the absorption, various advanced technologies were developed, namely, microneedle technology, iontophoresis, electroporation, sonophoresis and biochemical enhancement. Indeed, even these molecules are targeted to the cells with the use of cell-penetrating peptides. In this review, delivery of the peptide and protein therapeutics using oral, transdermal and other routes is discussed in detail.

Glyco-nanoparticles: New drug delivery systems in cancer therapy

Cancer is known as one of the most common diseases that are associated with high mobility and mortality in the world. Despite several efforts, current cancer treatment modalities often are highly toxic and lack efficacy and specificity. However, the application of nanotechnology has led to the development of effective nanosized drug delivery systems which are highly selective for tumors and allow a slow release of active anticancer agents. Different Nanoparticles (NPs) such as the silicon-based nano-materials, polymers, liposomes and metal NPs have been designed to deliver anti-cancer drugs to tumor sites. Among different drug delivery systems, carbohydrate-functionalized nanomaterials, specially based on their multi-valent binding capacities and desirable bio-compatibility, have attracted considerable attention as an excellent candidate for controlled release of therapeutic agents. In addition, these carbohydrate functionalized nano-carriers are more compatible with construction of the intracellular delivery platforms like the carbohydrate-modified metal NPs, quantum dots, and magnetic nano-materials. In this review, we discuss recent research in the field of multifunctional glycol-nanoparticles (GNPs) intended for cancer drug delivery applications.

Ionically Cross-Linked Chitosan Nanoparticles for Sustained Delivery of Docetaxel: Fabrication, Post-Formulation and Acute Oral Toxicity Evaluation

Introduction

Polymeric nanoparticles are potential carriers for the efficient delivery of hydrophilic and hydrophobic drugs due to their multifaceted applications. Docetaxel is relatively less hydrophobic and twice as potent as paclitaxel. Like other taxane chemotherapeutic agents, docetaxel is not well tolerated and shows toxicity in the patients. Nanoencapsulation of potent chemotherapeutic agents has been shown to improve tolerability and therapeutic outcome. Therefore, the present study was designed to fabricate chitosan and sodium tripolyphosphate (STPP) based on ionically cross-linked nanoparticles for sustained release of docetaxel.

Methods

Nanoparticles were prepared by the ionic-gelation method by dropwise addition of the STPP solution into the chitosan solution in different ratios. CNPs were characterized for post-formulation parameters like size, zeta potential, scanning electron microscope (SEM), FTIR, DSC/TGA, pXRD, and in-vitro drug release, as well as for acute oral toxicity studies in Wistar rats.

Results and discussion

The optimized docetaxel loaded polymeric nanoparticles were in the size range (172.6nm–479.65 nm), and zeta potential (30.45–35.95 mV) required to achieve enhanced permeation and retention effect. In addition, scanning electron microscopy revealed rough and porous surface, whereas, FTIR revealed the compatible polymeric nanoparticles. Likewise, the thermal stability was ensured through DSC and TG analysis, and powder X-ray diffraction analysis exhibited solid-state stability of the docetaxel loaded nanoparticles. The in-vitro drug release evaluation in phosphate buffer saline (pH 7.4) showed sustained release pattern, i.e. 51.57–69.93% within 24 hrs. The data were fitted to different release kinetic models which showed Fickian diffusion as a predominant release mechanism (R²= 0.9734–0.9786, n= 0.264–0.340). Acceptable tolerability was exhibited by acute oral toxicity in rabbits and no abnormality was noted in growth, behavior, blood biochemistry or histology and function of vital organs.

Conclusion

Ionically cross-linked chitosan nanoparticles are non-toxic and biocompatible drug delivery systems for sustained release of chemotherapeutic agents, such as docetaxel.